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Intel Open Source License 

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END_LEGAL */
#include <signal.h>
#include <assert.h>
#include <stdio.h>
#include <set>
#include "pin.H"

UINT64 icount = 0;

const ADDRINT TargetPrefix = 0xb0000000;
const ADDRINT SwizzlePrefix = 0xb1000000;

LOCALFUN ADDRINT Prefix(ADDRINT val)
{
    return val & 0xff000000;
}

LOCALFUN BOOL TargetSpace(ADDRINT val)
{
    return Prefix(val) == TargetPrefix;
}

LOCALFUN BOOL SwizzleSpace(ADDRINT val)
{
    return Prefix(val) == SwizzlePrefix;
}

LOCALFUN BOOL SwizzleSpace1(ADDRINT val)
{
    return SwizzleSpace(val);
}

LOCALFUN ADDRINT Unswizzle(ADDRINT val)
{
    fprintf(stderr, "Unswizzling %p\n", (void*)val);

    assert(SwizzleSpace(val));

    return (val & ~ SwizzlePrefix) | TargetPrefix;
}

LOCALFUN ADDRINT Swizzle(ADDRINT val)
{
    fprintf(stderr, "Swizzling %p\n", (void*)val);

    assert(TargetSpace(val));

    return (val & ~ TargetPrefix) | SwizzlePrefix;
}

    

ADDRINT ProcessAddress(ADDRINT val, VOID *ip)
{
    if (TargetSpace(val))
        fprintf(stderr, "Unexpected reference to target space: %p at ip %p\n", (void*)val, ip);
    
    if (SwizzleSpace(val))
    {
        //fprintf(stderr, "Unswizzle ip %p\n", ip);
        return Unswizzle(val);
    }

    return val;
}

VOID SwizzleArg(ADDRINT * arg)
{
    ASSERTX(SwizzleSpace(*arg));
    *arg = ProcessAddress(*arg, 0);
}

// When an image is loaded, check for a MyAlloc function
VOID Image(IMG img, VOID *v)
{
    //fprintf(stderr, "Loading %s\n",IMG_name(img));
    
    for (SEC sec = IMG_SecHead(img); SEC_Valid(sec); sec = SEC_Next(sec))
    {
        //fprintf(stderr, "  sec %s\n", SEC_name(sec).c_str());
        for (RTN rtn = SEC_RtnHead(sec); RTN_Valid(rtn); rtn = RTN_Next(rtn))
        {
            //fprintf(stderr, "    rtn %s\n", RTN_name(rtn).c_str());
            // Swizzle the return value of MyAlloc
            
            if (RTN_Name(rtn) == "_MyAlloc" || RTN_Name(rtn) == "MyAlloc")
            {
                RTN_Open(rtn);
                
                fprintf(stderr, "Adding swizzle to %s\n", "MyAlloc");
                RTN_InsertCall(rtn, IPOINT_AFTER, AFUNPTR(Swizzle), IARG_REG_VALUE, REG_GAX, IARG_RETURN_REGS, REG_GAX, IARG_END);
                RTN_Close(rtn);
            }

            if (RTN_Name(rtn) == "_MyFree" || RTN_Name(rtn) == "MyFree")
            {
                RTN_Open(rtn);

                fprintf(stderr, "Adding unswizzle to %s\n", "MyFree");
                RTN_InsertCall(rtn, IPOINT_BEFORE, AFUNPTR(SwizzleArg), IARG_FUNCARG_ENTRYPOINT_REFERENCE, 0, IARG_END);
                RTN_Close(rtn);
            }
        }
    }
}

VOID RewriteIns(INS ins)
{
    //fprintf(stderr,"Rewriting %p\n",(void*)INS_Address(ins));
    
    if (INS_ChangeMemOpToBaseRegisterAddressMode(ins, MEMORY_TYPE_READ, REG_INST_G0))
    {
        INS_InsertCall(ins, IPOINT_BEFORE,
                       AFUNPTR(ProcessAddress),
                       IARG_MEMORYREAD_EA,
                       IARG_INST_PTR,
                       IARG_RETURN_REGS, REG_INST_G0, IARG_END);
    }
    if (INS_ChangeMemOpToBaseRegisterAddressMode(ins, MEMORY_TYPE_WRITE, REG_INST_G1))
    {
        INS_InsertCall(ins, IPOINT_BEFORE,
                       AFUNPTR(ProcessAddress),
                       IARG_MEMORYWRITE_EA,
                       IARG_INST_PTR,
                       IARG_RETURN_REGS, REG_INST_G1, IARG_END);
    }
    if (INS_ChangeMemOpToBaseRegisterAddressMode(ins, MEMORY_TYPE_READ2, REG_INST_G2))
    {
        INS_InsertCall(ins, IPOINT_BEFORE,
                       AFUNPTR(ProcessAddress),
                       IARG_MEMORYREAD2_EA,
                       IARG_INST_PTR,
                       IARG_RETURN_REGS, REG_INST_G2, IARG_END);
    }
}

set<ADDRINT> SwizzleRefs;

BOOL SegvHandler(INT32 tid, INT32 sig, CONTEXT *ctxt, BOOL hndlr, void *)
{
    ADDRINT address = PIN_GetContextReg(ctxt, REG_INST_PTR);

    //fprintf(stderr, "Fault at %p\n",(void*)address);
    
    if (SwizzleRefs.find(address) != SwizzleRefs.end())
    {
        return true;
    }
    
    // The next time we see this address, it requires swizzling
    SwizzleRefs.insert(address);
    
    // Invalidate this instruction in code cache so it will be reinstrumented
    CODECACHE_InvalidateRange(address, address + 20);

    // returning from the signal handler will re-execute the instruction
    // this time it will be swizzled
    return false;
}

    
VOID Trace(TRACE trace, VOID *v)
{
    BOOL rewrite = false;
    
    for (BBL bbl = TRACE_BblHead(trace); BBL_Valid(bbl); bbl = BBL_Next(bbl))
    {
        for (INS ins = BBL_InsHead(bbl); INS_Valid(ins); ins = INS_Next(ins))
        {
            // If we see an instruction that needs rewriting, then rewrite all
            if (SwizzleRefs.find(INS_Address(ins)) != SwizzleRefs.end())
                rewrite = true;
        
            if (rewrite)
            {
                // If we suspect this instruction needs to be swizzled, generate safe, but slow code
                RewriteIns(ins);
            }
        }
    }
}

int main(int argc, char * argv[])
{
    PIN_InitSymbols();
    PIN_Init(argc, argv);

    TRACE_AddInstrumentFunction(Trace, 0);
    IMG_AddInstrumentFunction(Image, 0);
    
    PIN_AddSignalInterceptFunction(SIGSEGV, SegvHandler, 0);

    // Never returns
    PIN_StartProgram();
    
    return 0;
}